It is important for a number of reasons that a farmer must be able to determine the condition of their animals.
These reasons include:                being able to ensure that an animal is in optimum condition for optimal milk production, and        knowing the general wellbeing of the animal, and        knowing when to treat animals for various conditions, such as mastitis and heat stroke, and        oestrus onset.        
At present, these conditions can be determined by a number of ways, many of which are time consuming, labour intensive or inaccurate.
Reference will be made throughout the specification to the milking animal being a cow. However, it should be appreciated that the present invention could apply to other milking animals such as goats and sheep.
One of the conditions for which farmers are highly incentivised to diagnose and treat is mastitis. Early identification and treatment of sub-clinical mastitis can result in the infection period being greatly reduced. This in turn increases the productivity of the cow, as milk obtained from a mastitic animal is often dumped in order to maintain the quality of the milk to be collected.
There are numerous techniques for detecting mastitis—particularly using electrical conductivity. Udder temperature has also been identified as a potential indicator of mastitis. U.S. Pat. No. 7,277,744 describes one technique utilising infrared imaging of a cow's udder to identify inflammation associated with the onset of mastitis.
Infrared thermography has also been used to predict the onset of lameness by detecting inflammation in extremities, which is characterised by an increase in temperature. To date, the use of thermography to detect inflammation is labour intensive, requiring the capture of a thermographic image for each hoof and subsequent interpretation of the image by a skilled person. In a farming situation, workers are generally responsible for a range of tasks and the retention of a highly specialised technician is not cost efficient.
The dairy industry is also highly dependent on the oestrous cycle of a cow. Most modern farming techniques use artificial insemination of a cow to increase the value of bloodlines. This is a skilled procedure usually requiring a trained technician to visit the farm with multiple straws of semen stored in liquid nitrogen. The timing of when the cow is inseminated is critical. If the semen is administered at the wrong time of the cow's oestrous cycle, then a successful conception will not occur as it takes some time to determine whether a cow has been successfully inseminated, and considerable time can be wasted before the cow is inseminated again.
Another disadvantage of unsuccessful attempts at insemination is that multiple visits from the technician are required, which can be expensive—both in terms of the technician's time and the wasted semen.
Numerous attempts have been made to develop an accurate method for determining the onset of oestrus in cows.
Most commonly, these methods involve the detection of mounting by other cows—either by marking or detection of irritation. Other methods include the use of pedometers, or measuring the electrical resistance of reproductive tract secretions.
Experienced farmers and veterinarians can sometimes predict if a cow goes into oestrous through detecting a rise in skin temperature. It is known that during oestrous the cow's blood vessels dilate which should increase blood flow to the skin making it warmer and hence closer to core temperature than normal. It is also known that there can be a small (<0.5° C.) rise in core temperature as the cow goes into oestrous as well. However due to time intensive farming practices or the use of automated milking machines which milk cows through an entire 24 hour day, it is highly impractical for the farmer to consistently determine oestrous in this manner.
Techniques have been developed for measuring increases in temperature of the sexual organs of an animal, or using temperature to indicate rubbing from mounting in order to predict the onset of oestrus.
Although temperature measurements have been used to determine health related conditions in isolation, there remains a need for non-invasive detection of these conditions—preferably in an integrated system.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
Throughout this specification, the word “comprise”, or variations thereof such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.